Fiber optic breakout cassettes are passive, optical components that connect fibers between sets of cables. Such cassettes usually provided transition between multi-fibered connectors, such as MPO type connectors with MT ferrules, and single or dual fiber connectors, such as LC or SC type connectors. A typical fiber optic breakout cassette of the prior art is illustrated in FIG. 1. The function of this particular exemplary cassette 100 is to distribute the signals between the twelve fibers contained in fiber optic cable 103 and six dual-fiber cables 105. For instance, in a practical case, each dual-fiber cables 105 comprises one transmit channel and one receive channel. Hence, six of the fibers in the twelve-fiber cable 103 transmit data into and through the cassette to one of the fibers in each of the six dual-fiber cables 105. The other six the fibers in twelve-fiber cable 103 receive data through the cassette from the other one of the fibers in each of the six dual-fiber cables 105. Thus, multi-fiber cable 103 is terminated with a multi-fiber connector, such as an MPO plug connector 107. The six dual fiber cables 105 are each terminated with a dual fiber connector, such as dual fiber LC plug connectors 109. Alternately, each cable 105 could be terminated with two signal-fiber connectors. The cassette 100 comprises adapter 114 in an aperture in the wall of the housing 101 to which a twelve-fiber MPO-style receptacle connector 111 is attached on the inside of the housing for mating with the twelve-fiber MPO-style plug connector 107 at the end of cable 103. The cassette 100 further comprises six dual adapters 115 in apertures in the wall of the housing 101 to which twelve single-fiber LC-style receptacle connectors 113 are attached on the inside of the housing 101 for optically connecting to the six dual-fiber LC-style plug connectors 109 at the ends of fiber optic cables 105. Twelve individual fibers 117 are routed within the housing 101 between the back of the MPO receptacle connector 111 and the backs of the twelve LC receptacle connectors 113.
These optical cassettes 100 are rather expensive because they usually are assembled by hand by highly skilled workers and require connection of the fibers 117 to the connectors 111 and 113 at both ends of each fiber, which includes placing the fibers 117 into the ferrules of connectors 111, 113, epoxying the fibers in the connectors, polishing the end faces of the fibers, routing the fibers 117 within the tight space of the housing 101, and all the other steps normally associated with optical fiber terminations to connectors. Further, because the cassettes are hand-assembled, they are subject to human error and variability depending on operator skill and experience, especially with respect to improper fiber routing. In addition, assembly of a fiber optic cassette involves time-consuming, in-process testing, especially for higher speed components.
Even further, with the increasing prevalence of 40 GB and 100 GB per second optical networks, the breakout/consolidation in a fiber optic cassette involves multi-fiber connectors on both ends of the fibers since, in 40 GB and 100 GB networks, each channel now includes 4, 8, 10, or 20 fibers in parallel, rather than 2. With the channels now needing many more fibers, consolidation of these channels into larger fiber count trunks will be critical in the future as space inside data centers becomes more costly. As a consequence, the associated fiber routing inside the cassette becomes much more complex and prone to operator variability.
Power requirements for optical channels will be strict and space constraints will be significant. Hence, performance will need to be tightly controlled, such that tolerances will become increasingly strict and operator variability will become more and more problematic. This will lead to more costly, higher precision components, higher in-process testing costs, and increased levels of manufacturing rework and scrap.